The present invention relates to a water-removal press, and specifically to a water-removal press which uniformly presses the water-containing mass across its topography.
Textiles which are freshly washed and which come out of an automatically working and automatically unloading washing machine still contain a considerable quantity of water from the final washing operation or rinsing operation. This water must first be removed before the textiles can be conveyed to further treatment stations, for example, driers and/or mangle stations. Water-removal presses are usually used for removing the water from these textiles.
A known water-removal press (German Patent Specification No. 2,852,923) has a press table having a perforated plate and a collecting basket or filling frame in the form of a circular cylinder which is open on both sides. This filling frame is guided on a perpendicularly aligned guide and is moved into various vertical positions by means of a lifting device. In the case of the same plan form, the filling frame has a clearance width which is slightly larger than the outside dimensions of the press table. The filling frame can, therefore, be put over the press table and lowered relative to the latter until its upper edge is at about the same height as the press table upper side. On its top edge, the filling frame is provided with an outwardly protruding collar, the upper end face of which, i.e., the end facing away from the filling frame, is made in the shape of a truncated cone, and, in fact, with an obtuse cone angle. On the underside, the collar has a flat end face as a stop surface, by means of which the filling frame, in its lowered position, is supported on a support plate annularly enclosing the press table. Moreover, the water-removal press has a press piston which is likewise guided in alignment with the filling frame on a perpendicular guide and which can be moved into various vertical positions by means of an independent lifting device. This press piston has a rigid piston body in the form of a downwardly open bell, the opening of which is closed by a rubber-elastic diaphragm. The bell edge has the same plan projection as the collar of the filling frame and is made in the same manner, i.e., in the shape of a truncated cone.
The edge of the diaphragm sits against this bell edge and is connected there to the piston body by means of a metal clamping ring.
For removing water from textiles, the filling frame is moved into a vertical position in which its upper edge is above the press table to the extent that its lower edge reaches just slightly below the upper edge of the press table. When the press piston is raised, the wet textiles are brought, i.e., flushed, into the filling frame via a chute. The free water between the textiles runs off through the discharge openings in the press table and through the annular gap between the press table and the filling frame. The press piston, together with its bell edge, is lowered onto the collar of the filling frame.
Since this water-removal press works automatically just like the washing machine connected in front of it, textile parts which have been left behind on the comparatively slightly inclined collar of the filling frame during the flushing-in step can easily become jammed afterwards during the lowering movement between the metal collar of the filling frame and the metal clamping ring on the press piston and at least creased, if not quite damaged.
After the bell edge is placed on the collar of the filling frame, both parts are lowered further together relative to the press table until the collar sits on the supporting plate. In this vertical position, the upper edge of the filling frame is located approximately at the level of the upper edge of the press table. During this lowering movement, the textiles are held back from the press table. At the same time, the diaphragm comes into contact with the washing mass and is, first of all, extended into the inner space of the bell-shaped piston body. A pressure fluid is pressed into the intermediate space between the diaphragm and the bell base, by means of which the diaphragm compresses the washing mass on the press table, is largely pressing out the water from the washing mass. The removed water then runs off through the discharge openings in the press table.
The press piston is raised after the press operation is complete. The filling frame must likewise first be raised so that the pressed washing mass can be pushed away laterally from the press table. However, since the washing mass has not only been compressed vertically by the press operation, but, at the same time, has also been extended outwards, the washing mass sits against the inner wall of the filling frame with a considerable expanding force. The washing mass is often raised along with the filling frame when the latter is being raised. It can then only be removed from the filling frame with great difficulty. Since the water-removal press is part of a fully automatic washing line, this behavior of the washing mass leads to the automatic working sequence being disturbed very frequently. The operating personnel then have to intervene manually to restart the working sequence.
Another known water-removal press has a press base which is perforated. A filling frame in the form of a circular-cylindrical section open on both sides is arranged above this press base. The filling frame is displaceably guided on a perpendicularly aligned guide and can be lowered onto the press base and adjusted in various vertical positions by means of a lifting device. A press piston is guided in a vertically adjustable manner in alignment with the filling frame by means of a piston drive having a perpendicularly path of motion. The press piston has a rigid piston plate, on the underside of which is arranged a press pad or press cushion which has a circular-cylindrical edge part and a base part. The press cushion is filled with water which is pressureless in the normal condition, the volume of which remains unchanged.
At the start of the press operation, the press cushion in this water-removal press initially plunges only partially into the filling frame. While the press cushion sits against the washing mass, the internal pressure in the press cushion is increased. Consequently, the press cushion edge-part section still located outside the filling frame is extended radially. Moreover, in the case of a washing mass having a very variable filling level, the press cushion can be thrust up on one side, so that the radial expansion is intensified at this location. As a result of this press cushion dislocation on one side, individual textile parts can even be pushed out on the raised side.
During the further downward movement of the press piston and the press cushion, the expanded edge part of the press cushion, and therefore the edge part sitting on the edge of the filling frame, must be radially compressed while overcoming considerable frictional forces and, at the same time, be pressed axially into the filling frame. Even if the edge part has completely entered the filling frame, this frictional force is maintained during the further lowering movement of the press piston, because the internal pressure of the press cushion still acts radially on the edge part.
In the case of the frequently occurring, non-uniform filling level of the material to be pressed, only the portion with the higher filling level is correctly pressed out. On the other hand, the areas of the washing mass with an initially lower filling level are only inadequately pressed out.
In this press, the piston plate above the press cushion must be adapted with a very close fit to the clearance width of the filling frame, so that, when the press cushion is plunging into the filling frame, an annular gap does not remain open between the filling frame and the edge of the piston plate, into which annular gap the edge part of the press cushion could be pushed by the high internal pressure, which would be damaging for the press cushion, especially its edge part. On the other hand, however, this close fit between the piston plate and the filling frame has the great disadvantage that those items of washing which are left behind by chance on the edge of the filling frame or which have been pushed away towards the edge area during the press operation could become jammed between the metal piston plate and the metal filling frame and in so doing, could even be sheared off.